1. Field of the Invention
This invention relates in general to movable doors and more specifically to fire doors.
2. Description of the Prior Art
Heretofore, various fire doors have been developed. See, for example, Knopf, U.S. Pat. No. 1,112,071, and Saino, U.S. Pat. No. 3,763,612. None of the above patents disclose or suggest the present invention.
The National Fire Protection Association, in Pamphlet 80, defines a labeled fire door assembly as "a combination of a fire door, hardware and other accessories which together provide a specific degree of protection to an opening and to which has been attached a label, symbol or other identifying mark of a nationally recognized testing laboratory, inspection agency, or other organization concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling is indicated compliance with nationally recognized standards or tests to determine suitable uses in a specified manner." One problem with such labeled fire door assemblies is that for egress purposes various building codes and the like require any building having a slide-type fire door to also have a hinged-type personnel door. The normal practice in the past has been to provide a hinged-type personnel door in the wall of the building adjacent a slide-type fire door.
The following patents relate in general to the present invention: Neller, U.S. Pat. No. 1,184,983; Norton, U.S. Pat. No. 1,266,980; Ferris, U.S. Pat. No. 1,288,861; Graves, U.S. Pat. No. 1,506,925; Urquhart, U.S. Pat. No. 2,739,645; Carlo, U.S. Pat. No. 3,090,424; Szwartz, U.S. Pat. No. 4,081,018. None of the above patents disclose or suggest the present invention.